How to Prepare the Patio Site
1n Measure the slope of the patio to determine if you need to do grading
QUIK-DATA
Cost l l l
Skill l l
Time l l l l
TOOLS
Rope, carpenter’s square, hand maul,
tape measure, mason’s string, line
level, spade, sod cutter, straightedge,
level, wheelbarrow, shovel, hand
tamper, circular saw, drill, paintbrush,
concrete finishing tools, stiff-bristled
broom.
MATERIALS
2 × 4 lumber, 3" screws, compactible
gravel, vegetable oil or commercial
release agent, concrete mix or crackresistant concrete mix, acrylic cure
& seal.
Patios
A poured concrete patio can be a gray, utilitarian slab or it may be a highly
decorative focal point of your backyard living environment. By including a
decorative finishing technique in your plans, such as exposed aggregates
or etching with acid stain (see pages 112 to 113), your design options
are virtually unlimited. A concrete patio also may serve as a subbase for a
mortared flagstone, tile, or paver patio.
Building a concrete patio (or any concrete slab) is similar in many ways to
the walkway project on the previous pages (10 to 15). Before beginning
your project be sure and read through these pages for additional
information, particularly on the subjects of finishing and curing. If your
patio is larger than 10 ft. x 10 ft., you will definitely need to include control
joints. You’ll also want to consider buying or renting a power concrete
mixer—see page 138 for a chart on estimating how many bags of concrete
your patio will require.
QUIK-TIP
Contact your public utility company and have buried electric and gas lines
marked before you begin to dig for this or any other project.
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n QUIKRETE® GUIDE TO CONCRETE
work before you start your project. First, drive stakes at each end of the project
area. Attach a mason’s string between the stakes and use a line level to set it
at level. At each stake, measure from the string to the ground. The difference
between the measurements (in inches) divided by the distance between
stakes (in feet) will give you the slope (in inches per foot). If the slope is greater
than 1" per foot, you may need to regrade the site.
2 n Dig a test hole to the planned
depth so you can evaluate the soil
conditions and get a better idea of
how easy the excavation will be. Sandy
or loose soil may require amending;
consult a landscape engineer.
Shown cutaway
Isolation joint
Compactible gravel subbase
Shown cutaway
3 n Add a compactible gravel subbase to provide a
level, stable foundation for the concrete. The compactible
grave l a l s o i m p rove s d ra i n a g e — a n i m p o r t a nt
consideration if you are building on soil that is high in
clay content. For most building projects, pour a layer of
compactible gravel about 5" thick, and use a tamper to
compress it to 4".
4 n When pouring concrete next to structures,
glue a 1⁄2"-thick piece of asphalt-impregnated fiber board
to the adjoining structure to keep the concrete from
bonding with the structure. The board creates an isolation
joint, allowing the structures to move independently,
minimizing the risk of damage. u
Walkways, Patios & Steps n
17
How to Lay Out & Excavate a Patio Site
3 ft.
Level line
Slope line
4 ft.
5 ft.
1 n Lay out a rough project outline with a rope
or hose. Use a carpenter’s square to set perpendicular
lines. To create the actual layout, begin by driving wood
stakes near each corner of the rough layout. The goal is to
arrange the stakes so they are outside the actual project
area, but in alignment with the borders of the project.
Where possible, use two stakes set back 1 ft. from each
corner, so strings intersect to mark each corner (below).
Note: In projects built next to permanent structures, the
structure will define one project side.
2 n Connect the stakes with mason’s strings.
The strings should follow the actual project outlines. To
make sure the strings are square, use the 3-4-5 triangle
method (see page 149): measure and mark points 3 ft. out
from one corner along one string, and 4 ft. out along the
intersecting string at the corner. Measure between the
points, and adjust the positions of the strings until the
distance between the points is exactly 5 ft. A helper will
make this easier.
5 n To direct water runoff, most concrete surfaces
should have a slight slope, especially if they are near your
house. To create a slope, shift the level mason’s strings
on opposite sides of the project downward on their
stakes (the lower end should be farther away from the
house). To create a standard slope of 1⁄8" per ft., multiply
the distance between the stakes on one side (in feet) by
1⁄8. For example, if the stakes were 10 ft. apart, the result
would be 10⁄8 (11⁄4"). You would move the strings down
11⁄4" on the stakes on the low ends.
6 n Start excavating by removing the sod. Use a
sod cutter if you wish to reuse the sod elsewhere in your
yard (lay the sod as soon as possible). Otherwise, use a
square-end spade to cut away sod. Strip off the sod at
least 6" beyond the mason’s strings. The subbase should
extend at least 6" beyond the project area. You may need
to remove the strings temporarily for this step.
Line level
3 n Reset the stakes, if necessary, to conform to
the positions of the squared strings. Check all corners
with the 3-4-5 method, and adjust until the entire project
area is exactly square. This can be a lengthy process with
plenty of trial and error, but it is very important to the
success of the project, especially if you plan to build on
the concrete surface.
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n QUIKRETE® GUIDE TO CONCRETE
4 n Attach a line level to one of the mason’s strings
to use as a reference. Adjust the string up or down as
necessary until it is level. Adjust the other strings until
they are level, making sure that intersecting strings
contact one another (this ensures that they are all at the
same height relative to ground level).
7 n Make a story pole as a guide for excavating the site. First,
measure down to ground level from the high end of a slope line. Add 71⁄2" to
that distance (4" for the subbase material and 31⁄2" for the concrete if you are
using 2 × 4 forms). Mark the total distance on the story pole, measuring from
one end. Remove soil from the site with a spade. Use the story pole to make
sure the bottom of the site is consistent (the same distance from the slope
line at all points) as you dig. Check points at the center of the site using a
straightedge and a level placed on top of the soil.
8 n Lay a subbase for the project
(unless it requires a frost footing).
Pour a 5"-thick layer of gravel, and
tamp until the gravel is even and
compressed to 4" in depth. u
Walkways, Patios & Steps n
19
How to Build & Install Patio Forms
1 n A form is a frame, usually
made from 2 × 4 lumber, laid around
a project site to contain poured
concrete and establish its thickness.
Cut 2 × 4s to create a frame with
inside dimensions equal to the total
size of the project.
2 n Use the mason’s strings
that outline the projec t as a
reference for setting form boards in
place. Starting with the longest form
board, position the boards so the
inside edges are directly below the
strings.
4 n Drive 3" Deck Screws through the stakes and into
the form board on one side. Set a level so it spans the staked
side of the form and the opposite form board, and use the
level as a guide as you stake the second form board so it is
level with the first. For large projects, use the mason’s strings
as the primary guide for setting the height of all form boards.
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How to Pour & Finish a Patio
n QUIKRETE® GUIDE TO CONCRETE
3 n Cut several pieces of 2 × 4
at least 12" long to use as stakes.
Trim one end of each stake to a
sharp point. Drive the stakes at 3-ft.
intervals at the outside edges of the
form boards, positioned to support
any joints in the form boards.
5 n Once the forms are staked and leveled, drive
3” deck screws at the corners. Coat the insides of the
forms with vegetable oil or a commercial release agent
so concrete won’t bond to them. Tip: Tack nails to the
outsides of the forms to mark locations for control joints.
See page 14 for joint placement recommendations.
1 n Install reinforcement (optional) such as rebar
and rewire set on bolsters (inset photo), and then mix and
pour the concrete (see pages 12 to 15 and 138 to 143). The
use of fiber-reinforced crack-resistant concrete eliminates
the need for wire reinforcing mesh.
2 n Screed concrete level with the forms. Use a 2 x 4 in
a sawing motion to level and remove excess concrete.
3 n Float the concrete surface to create a surface
that is both smooth and skid resistant. Wait until bleed
water has disappeared before proceeding. Finish options
include a broomed finish, a smooth steel-trowel finish or
seed with small aggregate after floating.
4 n Cut control joints in larger patios. Lay a 2 x 4
straightedge guide on the surface and carefully tool
control joints using a grooving tool. Allow the concrete
to dry until sheen disappears, and then treat with acrylic
cure and seal (see page 15). u
Walkways, Patios & Steps n
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